Add explicit CMake .libs implementation that returns an empty list; same for .headers (#35816)

var/spack/repos/builtin/packages/cmake/package.py

@@ -436,6 +436,22 @@ def setup_dependent_package(self, module, dependent_spec):
         module.cmake = Executable(self.spec.prefix.bin.cmake)
         module.ctest = Executable(self.spec.prefix.bin.ctest)
 
+    @property
+    def libs(self):
+        """CMake has no libraries, so if you ask for `spec['cmake'].libs`
+        (which happens automatically for packages that depend on CMake as
+        a link dependency) the default implementation of ``.libs` will
+        search the entire root prefix recursively before failing.
+
+        The longer term solution is for all dependents of CMake to change
+        their deptype. For now, this returns an empty set of libraries.
+        """
+        return LibraryList([])
+
+    @property
+    def headers(self):
+        return HeaderList([])
+
     def test(self):
         """Perform smoke tests on the installed package."""
         spec_vers_str = "version {0}".format(self.spec.version)